[steveplace]

I'd much rather have 10,000 independent bets each with a 0.5% edge than 10 independent bets each with a 20% edge.

Not with trading, you want to cut losses quick and let winners run. The model behind Long Term Capital Management, as well as a ton of quant firms that went under this past Q, was the take-a-bunch-of-trades-for-small-profit... and it works until you get a six sigma event (see 2008).